I would say scoop it, and the little brothers too. you couls sell or trade the siblings to pay for parts you need.
not sure on the track width for those big fender trucks, you could check an assembly manual to get dimensions, but you could likely throw that cab and front end onto a newer frame for sure, witha diesel if desired, and keep the tires inside the fenders so it looks right.
here is a link to a site that may have the info you need. dunno for sure. it likely has cab dimensions though.
http://chevy.oldcarmanualproject.com...esto/index.htm
this should be a page with a dually that has the track width info
http://chevy.oldcarmanualproject.com...esto/53074.htm
this site has come in handy several times, possibly good to bookmark it for future reference.